Fluid strut



Jan. 26, 1932.

B. BocaosLowsKY FLUID STRUT Filed March 15', 1930 lNVENToR l .Patented Jan'. 216, 1932 UNITED' ISTATES I PATENT 'ori-Ica BORIS OGSLOWSKY, F STRATISORD, CONNECTICUT; ASSIGNOR TO SIKOBSKY AVIA- TIGN CORPORATION, 0F WILMINGTON, DELAWARE, A ,CORPORATION 0F DELAWARE FLUID STRUT rlhe present invention relates generally to automatically releas'able means for automatically locking cooperating cylinder and piston elements against relative 'movement at any desired point of their permissible relative movement. While I shall describe the vinvention as applied to telescoping elements, such as are used to project and retract the landing wheels of amphibians, it will be unjo derstood that this embodiment of the inven-4 tion is merely illustrative and in no sense restrictive. As applied to such telescoping members, the present invention is preferably so adapted as to lock the members together it at each limit of their relative movement.

ln the accompanying drawings,

Figure 1 is a longitudinal section, with parts in elevation, of a telescopic wheel controlling member of an amphibian.

Figure 2 is an enlarged section of a portion of the device of Figure 1, and

ure 2.

' Referring to the drawings, reference numeral 10 designates a cylinder closed at its upper end by means of a cap 11 threaded thereto, thevcapbeing provided with 'an external diametrical Bange 12 provided with an aperture 13 by means of which the upper end of the device is operatively connected with appropriate mounting means provided on the amphibian. The interior of the cap is provided with an annular groove 14, and above this groove is an aperture 15 through which Huid under pressure is adapted to be supplied, and the pressure iuid utilized may be either hydraulic or pneumatic.

rlhe lower end of cylinder 10 has threaded thereto a cap 16 provided with a central bore 17, in the walls of which is an annular groove containing a compressible packing 1S. Cap 16 is further provided with an -internal annular `groove 19, and with lan inlet 2() for the pressure fluid.

Within cylinder 10 is reciprocable a piston' 21 provided with acentral leather or similar packing ring 24. At its lower end piston 21 has integral therewith a coaxial boss 25 having a reduced threaded extremity 26 with which is engaged the interiorly threaded end Figure 3 is a section on line 3 3 of Fig-v Application led March 15, 1930. Serial No. 436,113.

4of an elongated tubular member 27 which passes through aperture 17 of cap 16. The lower closed end 28 of me'mber 27 is provided with an axial aperture through' which is passed a rod headed at its upper end at 30 to provide a seat for a compression spring 31 which is interposed between it and the lower face of boss 25. At its lower end rod 29 is provided with an eyeletted flange 32 for attachment to the swingable landing wheel bracketof the amphibian.

Piston 21 is provided with an axial bore 33 in which is slidable a closely itting plunger 34, whose travel is limited 'by suitable abutments 35 and 36. Fixed in coaxial relation to plungerv34 and ext-ending in 0pposite directions are pins 37 and 38 provided with heads 39 and 40,respectively. Spring seat 41and 42 are slidable on pins 37 and 38, and interposed between these seats and the plunger are power storing devices, such as compression springs 43 and 44.

Adjacent the ends of bore 33 diametrical slots 45 and 46 are formed in the piston body, these slots adjacent each end being of substantially rectangular cross-section and havingvparallel walls for slidably guiding pairs of lugs 47, 48 and 49, 50.

Spring seat 41 is provided with diametrically opposite ears to which are pivoted toggle links 51 and 52 which, at their other ends, are pivoted to ears formed on lugs 47 Tand 48. In the same Way spring seat 42 is provided with ears to which are pivoted toggle links 53 and 54 which, at their other ends are pivoted to ears formed at the rear of lugs 49 and 50. -Slots 45 and 46 are suitably iiared in the direction of bore 33 to permit pivotal movement of the toggle links relative to their respective lugs.

In using the present invention, a wheel axle is preferably hingedly attached at the bottom of that portion 0I" thepiston extending below the main cylinder of the strut,

which piston telescopes upward into the cylinder by means of Huid forced into the strut cylinder through the hole near the bottom of the cylinder. i

Preferably, bore 33 will extend from the top of piston 21 into boss 25 to form a recess 55 in the hater mi 1u s 35 and 3e win be screw attached at suitab e points on the walls of the bore. In recess 55 a clearance is provided for head 40 of pin 38, while a clear ance for head 39 of pin 37 is provided in the'upper end of the bore. A pair ofducts 56 and 57 communicate recess 551with the interior of cylinderlO below the main piston body.

relative movement of the plun erv is tended;

to be transmitted to lugs 49 an 50 through spring 44, seat 42 and links 53, 54. Inasmuch as lugs 49 and 50 are in contact with the continuous interior wall of the cylinder their projection beyond thef piston periphery 1s prevented and spring 44 is merely' compressed. As soon, however, as slot 46 comes into register with recess 19 lugs 49 and 50V will be projected into the recess and will thus lock the piston against upward movement in the cylinder. l When, however, it is desiredV to move the piston upwardly in the cylinder and pressure Huid is accordingly introduced through inlet 20, the fluid passes through ducts 56 and 57, and moves plunger 34 upwardly relative to piston 21, whereupon head 40 of pin 38 abutting the underside of seat 42 moves the latter upwardly and through the intermediary of links 53 and 43 ietracts lugs 49 and 50. The described coaction of head 40 and seat .42 is illustrated in Figure 2 by the cacting relation of head 39 and-seat 41. It will be understood that simultaneou'sly with the retraction of lugs 49 and 50 from recess 19 spring 43 is compressed so as to project lugs 47 and 48 into recess 14 when the piston reaches the top of the cylinder.

From this description it` is obvious that means actuated in dependence upon the inlugs in engaging troduction of pressure fluid into the cylinder have been providedfor locking the piston at its limits of travel, and that these same means y are automatically actuated to unlock the piston upon the introductionof pressure fluid to move it to its other limit position.

When, 'for-example, lugs 49 and 50 have been projected into recess 19 the inner ends of links 53Y and 54 may be permitted to move slightly below the horizontal or below the dead center line, thu's effectively locking the relation with the recess. In any event there is no direct retractive effort exerted against the lugs when landing impact is transmitted to the piston, so that even upon complete failure Vof the operating uid .slidable in said slot and above the piston, collapse of the telescoping members will be prevented. Landing impacts sare transmitted to the piston through damping spring 31, as will be understood.

I claim: 1.'In combination, therein, said cylinder having openings 'at its .opposite ends to admit fluid under pressure,

a cylinder, a piston cess upon admission of pressure fluid to the other end of the cylinder.

2. In combination, a cylinder, a piston reciprocable in said cylinder, said cylinder having openings at its opposite ends to admit fluid under pressure, said piston having a substantially axial bore therein, a plunger in said bore, a substantially radial piston adjacent an end of said bore, a lug projectible beyond the piston periphery, said cylinder having a recess adapted to receive said lug when the latter is in register therewith, and means for projecting said lug in dependence upon movement ofthe plunger relative to the piston due to the introduction of pressure fluid into one end of thecylinder slot in said ing said lug upon introduction of pressure fluid into the other end of the cylinder.

3. In combination, a cylinder, a piston re- Y ciprocable in said cylinder, said cylinder havlng openings at its opposite ends to admit fluld under pressure, said piston having a substantially axial bore therein, a plunger in said bore, a substantially radial slot in said piston adjacent an end of said bore, a lug .-slidable in said slot and projectible beyond the piston periphery, said cylinder having a recess adapted to receive said lug when 'the latter is `in` register therewith, andl means for projecting said lug in dependence upon movement of the plunger relative to the pisros ton due to the introduction of pressure iuid into one end of the cylinder and for retracting said lug upon lntroduction fluid into the other end of the cylinder.

4. In combination, a cylinder, a piston reciprocable in said cylinder, said cylinder having openings at its oppositeends to admit fluid under pressure, said piston having a substantially axial bore therein, a plunger in said bore, a substantially radial slot in said piston adjacent an end .of said bore, a lug slidable in said slot and projectible beyond the piston periphery, said cylinder having a recess adapted to receive said lug when the latter is in register therewith, a spring comof pressure' l n in saidk bore,

pressed upon movement othe plunger 'substantially axial bore therein, a

the piston periphery, said pressed upon movementof the plunger relative to the piston due to the introduction of -pressure fluid into one end ofthe cylinder,

and means actuated upon expansion of the spring to project the lug into the recesswhen the two come into register vand for retractin the lug upon introduction of pressure ilui into the other end of the cylinder;

5. In combination, a cylinder, a piston reciprocable in said cylinder, said cylinder having openings at its opposite ends to admit fluid under pressure, said piston having a substantial-ly axial bore therein, a plunger a substantiall radial slot in said piston adjacent an endv o said bore, a lug slidable in said slot and projectible beyond the piston periphery, said cylinder having a recess adapted to receive said lug when the latter is in register therewith, a spring conre ative to the piston dueto the introduction of pressure fluid into `one end of the cylinder, and a toggle link actuated upon expansion of the spring to project the lug into the recess when the two come into register and for reti-acting the lug upon introduction of pressure iiuid into the other end of the cylinder.

6. In combination, a cylinder, a piston reciprocable in said cylinder, said cylinder having openings at its opposite ends toadmit fluid under pressure, said piston havinga said bore, a substantially radial s piston adjacent an end of said bore, a lu slidable in said slot and projectible beyon the piston periphery, said cylinder havmg a recess adapted to receive said lug when the latter is in register therewith, a spring com; pressed upon movement of the plunger'relathe piston due to the introduction of lpressure fluid into one end of the cylinder, a toggle link actuated upon expansion of the spring to project the lug into the recess when the two come into register, and means connected with theplunger for retractingthe lug upon introduction of pressure fluid into the other end of the cylinder.

,7., ln combination, a cylinder, a piston rej ciprocable in said cylinder', said cylinder having openings at its opposite ends to admit fluid under pressure, said piston having a substantially axial bore therein, a plunger in said bore, a diametrical slot in said piston adjacent an end of said bore, a lug slidable in each end of said slot and projectiblebeyond c linder having recesses .adapted to receive sai lugs when the latter are in, register therewith, a pin fixed 'to and v projecting longitudinally of said lunger in the direction of said slot and havmg a 'head at its free end, a spring seat slidable on said pin, a compresslon spring interposed between theplunger and seat, and toggleY links connecting the seat and lugs.

8. 'In combination, a cylinder, a piston replunger 1n 5t in'v said nings atits opposite ends to admit.

axial .bore therein, a plunger 1nA oppositely beyond lthe piston peripher ,said

cylinder having recesses at one end a apted to receive onepair of said lugs and recesses at the other end adapted to receive the other pair of said lugs, a headed pin projecting longitudinally from each end of said plunger, a spring a compression spring interposed between each of said seats and the plunger, toggle links connecting one of said seats and one of said pairs of lugs, and toggle links connecting the other of said seats and thj other of said pairs of lugs.

Signed at Stratford, Connecticut, in the county of Fairfield and S'tate of Connecticut, this 4th d`ay of March, A. D. 1930.

l BORIS BOGQSLOWSKY. 

